1. Field of the Invention
The present invention relates to a valve for an anti-lock brake system. More particularly, to a valve for an anti-lock brake system, capable of reducing the cost of production through structural improvement of a valve housing.
2. Description of the Related Art
In general hydraulic brakes of vehicles, hydraulic pressure is applied to a master cylinder by operation of a brake pedal, and thereby braking is carried out. At this time, when braking force greater than static frictional force between a road surface and a tire is applied to the tire, there occurs a slip phenomenon in which the tire slides on the road surface.
However, since a kinetic frictional coefficient is smaller than a static frictional coefficient, this slip phenomenon must be prevented in order to ensure optimal braking. Further, a steering wheel locking phenomenon that makes it impossible to control a steering wheel when the brake is operated must be prevented.
Thus, it is an anti-lock brake system that controls the hydraulic pressure applied to the master cylinder to prevent these phenomena. The anti-lock brake system basically comprises a plurality of solenoid valves, an electronic control unit (ECU) for controlling the solenoid valves, an accumulator, and a hydraulic pump.
Referring to FIG. 1, a conventional solenoid valve is installed on a modulator block 1 in order to increase compaction, and a valve bore 2 is bored in the modulator block 1 such that a valve can be installed.
A hollow valve housing 3 having an inlet 3a and an outlet 3b, both of which are connected with inner channels of the modulator block 1, is installed in the valve bore 2.
A cylindrical sleeve 5 is coupled to one end of the valve housing 3 such that an armature 4 can move backward and forward in the cylindrical sleeve. The sleeve 5 is coupled with a valve core 6 at an open end thereof, in which the valve core 6 functions to close the open end of the sleeve 5 and move the armature 4 backward and forward.
Further, the armature 4 extends toward a valve seat 7 in a hollow space so as to shut off and close an orifice 7a of the valve seat 7 through backward and forward movement. At this time, an elastic member 8 applying elastic force to the armature 4 is installed between the armature 4 and the valve core 6.
This conventional solenoid valve has a structure in which the valve housing 3 has the inlet 3a and the outlet 3b serving as an inflow port and an outflow port and includes the valve seat 7 press-fitted thereinto.
However, this structure of the solenoid valve increases its entire size because the valve seat 7 is installed in the valve housing 3, and inevitably requires to machine the valve housing 3 in a complicated shape because the inlet 3a and the outlet 3b must be formed in the valve housing 3 in a radial direction and in a longitudinal direction.
Thus, the modulator block 1 is increased in size, and is accompanied with complicated machining. This serves as a factor of increasing the overall cost of production of the anti-lock brake system.